What characterizes a restrictive lung disorder?

A restrictive lung disorder is characterized by reduced lung expansion and a decreased total lung capacity. This means that the lungs cannot fully expand during inhalation, leading to a lower volume of air that can be inhaled. Conditions such as pulmonary fibrosis, pneumonia, or chest wall deformities can cause this restriction. In restrictive disorders, the overall lung volume is diminished, which affects the airflow and gas exchange efficiency.

The other options do not accurately represent restrictive lung disorders. Increased lung capacity and expansion would indicate a condition contrary to restriction, while chronic obstruction of airflow is a hallmark of obstructive lung disorders rather than restrictive ones. Excessive lung compliance may suggest conditions like emphysema, which is also not aligned with restrictive diseases. Therefore, the correct answer reflects the fundamental characteristics of restrictive lung disorders.